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October 31, 2012 -- Annual prostate-specific antigen (PSA) screening yields a slightly greater quality-adjusted life expectancy among patients who have a high risk of developing metastatic disease compared to unscreened patients, according to research presented on Tuesday at the American Society for Radiation Oncology (ASTRO) annual meeting.

Findings from the study run counter to the U.S. Preventive Services Task Force (USPSTF) recommendation. This independent group of volunteers consisting of 16 national experts in prevention and evidence-based medicine has recommended against PSA screening for prostate cancer. The current study was presented at ASTRO by lead author Dr. Arie Dosoretz, a radiation oncologist in the department of therapeutic radiology at Yale-New Haven Hospital.

"The debate regarding PSA screening has centered on the indolent nature of prostate cancer, the lack of a proven mortality benefit specific to screening, and the potential for treatment-related harm," Dosoretz said. "We created a decision analytic model to calculate the quality-adjusted life expectancy associated with screening men for prostate cancer with annual PSA testing in order to provide further guidance on screening and treatment decisions."

The study, though independent from the European Randomized Study of Screening for Prostate Cancer (ERSPC), used findings from ERSPC published in 2009 and in 2012.

Dosoretz and colleagues randomized approximately 162,000 men ages 65 and older and followed results from their PSA screenings for 25 years. In men who screened positive for prostate cancer, the study assumed that they had clinically localized, low-risk prostate cancer and were treated with intensity-modulated radiation therapy (IMRT).

In men not screened for prostate cancer who presented with localized disease, the study assumed they also had low-risk disease and underwent subsequent treatment with IMRT. Long-term treatment-related adverse effects included the possibility of developing genitourinary toxicity, gastrointestinal toxicity, and sexual dysfunction.

The study created a model to compare quality-adjusted life expectancy in men with and without annual PSA screening to provide further guidance on screening and treatment decisions. When comparing screened versus nonscreened patients, the researchers found a slight benefit to screening, with a value of 13.70 quality-adjusted life years (QALYs) compared to 13.24 QALYs, respectively.

However, the benefit of annual PSA screening diminished with increasing age, and it depended on the probability of eventually developing metastatic cancer and an associated decrease in quality of life. For patients who had less than a 4.9% chance of developing prostate cancer within 10 years, the recommended strategy was to forgo annual screening.

"Factors contributing to whether or not a patient should be screened include the age and health of the patient, and the potential impact of screening and a prostate cancer diagnosis on their quality of life," Dosoretz said. "Future decision-making should account for individualized utilities and the economic costs associated with prostate cancer screening and treatment."